Anchors platform support

Understand the AR Foundation capabilities implemented by the OpenXR Spatial Entities anchor provider.

This package implements the following optional features of AR Foundation's XRAnchorSubsystem:

Feature	Descriptor Property	Supported
Trackable Attachment	supportsTrackableAttachments	Determined at runtime
Synchronous Add Anchor	supportsSynchronousAdd	Yes
Save Anchor	supportsSaveAnchor	Yes
Load Anchor	supportsLoadAnchor	Yes
Erase Anchor	supportsEraseAnchor	Yes
Get Saved Anchor Ids	supportsGetSavedAnchorIds	Yes
Async Cancellation	supportsAsyncCancellation	Yes

Automatically load saved anchors

The OpenXR Spatial Entities anchor provider supports the ability to automatically load all saved anchors. Refer to Feature reference to learn more about this capability.

Anchor feature support

Spatial Entities is a cross-runtime package. It runs on any spec-compliant OpenXR runtime, but Unity officially supports only Meta Horizon OS and Android XR. Support for individual anchor features can differ between runtimes.

Feature	OpenXR extension	Meta Horizon OS	Android XR
Anchors	XR_EXT_spatial_anchor	Yes	Yes
Trackable attachments	XR_ANDROID_spatial_entity_bound_anchor		Yes, planes only

For the platform-agnostic explanation of this feature, refer to Trackable attachments in the AR Foundation manual.